Various fluid delivery apparati, and particularly gas and aerosol delivery apparati, are well known in the medical industry. For example, the simple oxygen mask is shaped to fit around a patient's nose and mouth and is typically strapped into place with an elastic band or small tubing positioned around the patient's head. An aerosol mask is a cone-shaped shell, similar to the simple oxygen mask except that it acts as a 100 to 150 ml reservoir, has larger open ports for exhalation, and is connected to large bore tubing for higher volume flows from a nebulizer. Another type of delivery apparatus is a face mask, sometimes referred to as a face tent, which fits snugly under a patient's chin to provide aerosol to the patient's nose and mouth. This type of mask is open at the top, and can be used when the discomfort of an aerosol mask cannot be tolerated by the patient. Another type of delivery apparatus is the tracheostomy mask, which is held around the neck of the patient by an elastic band and fits directly over a stoma of the tracheotomy or the tracheostomy tube. The tubing connection of this type of mask swivels to allow for adjustment in the patient's position. Yet another type of delivery apparatus is the Briggs adaptor, also known as the T tube, which attaches directly to an endotracheal or tracheostomy tube of the patient.
It is clearly important for any type of delivery apparatus to remain positioned properly on the patient as aerosol or gas treatment of the patient it necessary. Frequently, however, due to discomfort created by such delivery apparati, a patient will often incorrectly reposition such an apparatus, or remove it altogether. Moreover, such delivery apparati may be inadvertently repositioned or removed from involuntary movement of a patient during sleep. Clearly, a nurse or respiratory practitioner should be immediately notified if such a delivery apparatus is shifted from proper placement so as to ensure that the patient is receiving the properly prescribed aerosol or gas therapy.
Several indicator devices have been used to alert medical personnel of improper conditions during a patient's gas or aerosol treatment. For example, a pressure indicating device described in U.S. Pat. No. 4,361,107 to Gereg on Nov. 30, 1982, uses a mechanical pop-out indicator to alert medical personnel of excess pressure in the delivery system. Another device taught in U.S. Pat. No. 4,474,175 to Hudimac, Jr., on Oct. 2, 1984, uses an electronic means to detect an over-abundance of nitrous oxide flowing to a patient's breathing mask. None of these devices, however, indicate when a delivery apparatus is incorrectly positioned on a patient.
Clearly there is a need for a liquid delivery apparatus that will alert health care staff of incorrect positioning of the apparatus on a patient. Such a needed device would be easy to use and monitor, and would not interfere with the delivery of the liquid to the patient. Moreover, such a needed device would be readily manufacturable in currently known delivery apparati, increasing the cost of such apparati only slightly. The present invention fulfills these needs and provides further related advantages.